Cobalt-intercalated one-dimensional nanocrystals of urea perylene imide polymer for enhanced visible-light photocatalytic water oxidation

• Published in: Applied catalysis. B, Environmental Environmental, 2022-07, Vol.309, p.121293, Article 121293
• Main Authors: Cao, Aihui, Li, Renfu, Xu, Xiao, Huang, Weifeng, He, Ying, Li, Junqiang, Sun, Miao, Chen, Xueyuan, Kang, Longtian
• Format: Article
• Language: English
• Subjects: Cobalt; Cobaltous nitrate; Crystals; Excitons; Heterojunctions; Nanocrystals; One-dimensional nanocrystal; Oxidation; Photocatalysis; Polymers; Rigidity; Silver nitrate; Urea; Urea perylene imide; Ureas; Water oxidation
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2022.121293

Urea perylene imide polymer (UPDI) is successfully recombined with Co(NO3)2 molecules into one-dimensional nanocrystals (Co−UPDI) for enhanced photocatalytic oxygen evolution (POE) under visible light. Co−UPDI as photocatalyst exhibits more an order of magnitude of POE rate than UPDI at pH = 4.8 (8.00 vs. 0.58 mmol h−1g−1), which is the highest among reported POE tests in aqueous colloid system with AgNO3 as sacrificial agent. The apparent quantum yield (AQY) reaches 4.39 % at 450 nm. The systematical experiments reveals that the heterojunction formation between UPDI line and Co(NO3)2 molecules is crucial through the coordination of Co with N atoms. Consequently, the rigidity of UPDI line enhances, H−type stacking of PDI moiety becomes closer, and CoOOH as cocatalyst in-situ forms during POE. Meanwhile, more excitons with longer lifetime generate and more quickly transfer in Co−UPDI than UPDI nanocrystals. This work provides an efficient strategy for photocatalytic water oxidation. 1D nanocrystals (Co-UPDI) of Co(NO3)2 −intercalated UPDI polymer were synthesized for visible-light photocatalytic oxygen evolution (POE) in acid colloid system. Co−UPDI as catalyst exhibits more an order of magnitude of POE rate of UPDI (8.00 vs. 0.58 mmol h−1g−1) due to UPDI rigidity enhanced and in-situ formation of CoOOH as cocatalyst. [Display omitted] •1D nanocrystals of UPDI molecule line and Co(NO3)2 composite are successfully synthesized.•POE rate is raised by more an order of magnitude in Co−UPDI than UPDI (8.00 vs. 0.58 mmol h−1g−1).•Z-scheme heterojunction between UPDI and Co(NO3)2 forms due to the interaction of Co with N.•The rigidity of UPDI molecule line, especially at C−N site, enhances in Co−UPDI crystal.•The longer lifetime of charge transfer exciton is found in Co−UPDI than UPDI (100.1 vs. 2.3 ps).